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Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4087
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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P only. I have a 2002 S500 with a drain, I replaced the

Customer Question

For Lou P only. I have a 2002 S500 with a drain, I replaced the battery and alternator with new bosch. I did a basic parasitic drain test with all the door / hood latches rigged shut, and vehicle had a drain of .3A, after pulling fuse after fuse, then waiting for the modules to sleep again almost each time, came up with a radio that was draining excessively, unplugged it and the drain went down to .07A. Returned the car, and was dead 2 days later. This must be something big that is also intermittent, because I don't think a .07A drain will kill battery like this. Your thoughts and guidance, please.
Submitted: 6 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 6 months ago.

Hello, my name is***** and i will do my best to assist you.I am going over your story now and will reply back soon with some info,thanks!

Expert:  Lou P. master tech replied 6 months ago.

so was the fuse put back in for the radio? or left removed? also the fuse powers more items then the radio.

Expert:  Lou P. master tech replied 6 months ago.

so lets start again, hook your meter up as you would, open all the doors, hood, trunk and latch the latches and lock the car with the meter hooked up. give it 20 minutes to stabalize and sleep then pull the fuses at the rear fuse box 1 at a time lets see what kills the draw.

Customer: replied 6 months ago.
I had to put the fuse back in because the door locks wouldnt work otherwise. Radio itself is currently unplugged
Expert:  Lou P. master tech replied 6 months ago.

oh right, i think i rememebr that, well reinserting the fuse will allow the draw to happen again.

so lets check that fuse first then we can see whats on the circuit and unplug the individual items.

Expert:  Lou P. master tech replied 6 months ago.

OK so lets first confirm that the draw is constant with the radio removed, if it is then we remove the fuse to see if the draw stops, if it does then we put the fuse back in and check the telephone module first, left side of the trunk with the amplifier and cd changer.

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